1. Field of the Invention
The present invention pertains to a system for providing useful energy from the solar radiation reaching the earth's surface. Man's energy demands during the past few hundred years have exceeded those of all the prior years in the life of the earth. This fact points out the staggering rate at which modern technological advances have taken place. These advances have greatly improved the lot of mankind in general. However, they have also cooperated with the ever increasing population of the earth to result in the energy demands mentioned above. Furthermore, continued technological developments and population increases can only be expected to further increase already high energy needs.
Traditionally, the energy to satisfy these needs has been provided by various combustible fuels, most frequently fossil fuels such as petroleum products, natural gas, and coal. However, these fuels are currently being used at a rate which is much greater than that at which they can be replaced by nature, and unless other energy sources are developed, these fuels will eventually be exhausted, albeit in the distant future.
Other problems are attendant upon the use of combustible fuels. One of these is that of pollution in the form of the various products of combustion of the fuels and of those portions of the fuels which are not burned. Another is that the processes for securing these fuels is often disruptive or destructive to the earth's various ecosystems.
One alternative to fuel combustion currently being used and further developed is that of atomic or nuclear energy. However, many experts hope to avoid widespread or increased use of this energy source as it is expensive and considered dangerous in terms of its lethal waste products, which must be isolated from the biosphere for extremely long periods of time, as well as in terms of possible disasters at the nuclear power plants.
Accordingly, much effort has recently been devoted to the development of solar energy systems. Solar radiation is a virtually inexhaustible source of energy, at least in terms of the potential lifespan of the earth. The vast portion of the solar radiation which reaches the earth is presently dissipated as waste heat. Furthermore, solar energy systems, by their very nature, tend to be less dangerous and less ecologically harmful than either nuclear energy systems or the burning of various fuels.
2. Description of the Prior Art
One prior system for using energy is disclosed in prior U.S. Pat. No. 3,832,853 to Butler. In this system, solar radiation striking the sides of an edifice is absorbed by blinds disposed between parallel window panes. The air adjacent the blinds is thus heated and begins to rise in the space between the window panes. From the top of this space, the moving air is directed to a fan which is driven thereby to rotate a shaft by which various other machines may in turn be driven. Since this system uses the air as a motive force, the space between the window panes must be left open so that air can enter, flow through, and leave the space. This leaves the blinds and any other parts which might be disposed in the space susceptible to rust, corrosion, dirt build-up, and various maintenance problems. Furthermore, the system provides no means for varying the disposition of the blinds in the space.
U.S. Pat. No. 2,484,127 to Stelzer discloses a system in which a heating space is formed between a transparent panel exposed to solar radiation and a dark opaque panel opposite the transparent one. Although the energy derived from the heated air is not provided by using the air as a motive force, the air must still flow through the heating space. Furthermore, the presence of the opaque panel precludes the possibility of using the device as or incorporating it in a window.
Another solar energy device is disclosed in U.S. Pat. No. 2,595,905 to Telkes. Here a system of blinds is disposed behind a transparent window or the like. The blinds do not absorb the solar radiation but rather reflect it onto a slab-like container of some heat-absorbing material. Again, visibility through the device is prevented.
U.S. Pat. No. 3,387,602 to Thomason discloses a solar heater comprising one or two panes of glass or the like. An overlayment having a dark surface facing the sun is disposed behind the glass. A fluid spreader is disposed between the dark surface and the glass to evenly distribute water or other liquid which is allowed to trickle down between the dark surface and the glass. Here too, the device must be open so that the water can enter and leave the heating space, and visibility through the device is not permitted.